A conveyor can comprise a track-bound car which is selfpropelled. A drive motor for the track-bound car can be supplied with a drive current by current-carrying rails, and a container on the track-bound car can be closable by means of a cover which can be locked by a latch of a locking mechanism containing at least one unlocking electromagnet.
A track-bound car of this type is described for example in German Patent document DE-OS No. 33 13 951. In this known conveyor, a stop code is provided at a generating station by a code setting mechanism. The electromagnetic unlocking mechanism affording access to the container remains idle and the container locked, until the control mechanism is given a correct code at a sensing station. The control mechanism then compares the code it is given with the locking code and operates the unlocking mechanism only when there is a coincidence between the codes. This arrangement for locking of the cover of the container is comparatively complicated and expensive, since at the generating station a mechanism for making and transmitting the lock code and a mechanism or circuit for operating and inputting the correct code at the sensing station are required. The track-bound car requires a comparatively complicated control mechanism, in order to compare the lock code with the validating code generated at the sensing station.